Page 390 - Biosystems Engineering

CHAPTER 13

Extraction, Refining,

and Stabilization of

Edible Oils

Michel Eskin
Department of Human Nutritional Science
University of Manitoba
Manitoba, Canada

Ahindra Nag
Department of Chemistry
Indian Institute of Technology
Karagpur, India

13.1 Introduction
Oils and fats are composed of different mixtures of glycerides of var-
ious fatty acids. Oil is an ester containing more unsaturated fatty
acids and having a lower melting point. The more saturated ester is a
fat and is generally solid.
The properties of fats depend on the type of fatty acids present,
whether they are saturated or unsaturated. Fatty acids are mostly
straight-chain aliphatic carboxylic acids. In certain fats, the straight
chain may be linked with cyclic or aromatic groups. With some excep-
tions, fatty acids are of even number of carbon atoms and have more
than 12 carbon atoms.

Saturated Fatty Acids Saturated fatty acids that are present in naturally
occurring fats are given below. The general formula is C H COOH,
n 2n+1
n-butyric (C ), isovaleric (C ), n-caproic (C ), n-caprylic (C ), n-capric
4 5 6 8
(C ), n-lauric (C ), n-myristic (C ), n-palmitic (C ), n-stearic (C ),
10 12 14 16 18
and a few others.
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